Technical Field
The present application relates to an intermediate transfer belt, image forming apparatus and image forming method.
Description of the Related Art
Conventionally, a seamless belt has been used as a member of an electrophotographic device for various uses. Especially, recent full-color electrophotographic devices employ an intermediate transfer belt system, in which developed images of four colors, yellow, magenta, cyan, and black, are superimposed on an intermediate transfer member temporarily, followed by being collectively transferred onto a transfer medium, such as paper.
As for the aforementioned intermediate transfer belt, a system using developing units of four respective colors to one photoconductor has been used, but this system has a problem in that a printing speed thereof is slow. Accordingly, to achieve high speed printing, a quadruple-tandem system has been used, where the tandem system includes providing photoconductors of four respective colors, and an image of each color is continuously transferred to paper. In this system, however, it is very difficult to accurately position images of colors to be superimposed, because the position of paper changes as affected by the environment, which causes displacement of the colors in the image. Accordingly, currently, an intermediate transfer belt system has been mainly adapted for the quadruple-tandem system.
Under the circumstances as mentioned above, the higher requirements for performance properties (e.g., high speed transferring, and accuracy for positioning) of an intermediate transfer belt have been demanded than before, and therefore it is necessary for an intermediate transfer belt to satisfy these requirements. Especially for the accuracy for positioning, it has been required to inhibit variations caused by deformation of an intermediate transfer belt itself, such as stretching, after continuous use thereof. Moreover, an intermediate transfer belt is desired to have flame resistance as it is provided over a wide region of a device, and high voltage is applied thereto for transferring. To satisfy these demands, a polyimide resin, polyamide imide resin, or the like, that is a highly elastic and highly heat resistant resin, has been mainly used as a material of an intermediate transfer belt.
Recently, full-color electrophotographic images have been more frequently formed on various types of paper such as slippery coated paper having high smoothness, recycle paper, emboss paper, Japanese paper, and craft paper having rough surfaces. The followability on papers having different surfaceness has importance, and poor followability causes uneven image density or color tone.
In order to solve this problem, various intermediate transfer belts each formed of a substrate and an elastic layer comparatively having flexibility layered thereon are disclosed. And a method of forming a protection layer is disclosed. However, when a material having fully high transferability is coated on the flexible layer, it is unable to follow flexibility thereof, resulting in cracking or peeling. Besides, in order to develop transfer ability intermediate transfer belts with adhered particles on the surface are disclosed.